I just bought a Sapphire Radeon HD 6950 2gb and a Rosewill 550W ATX12V / EPS12V Power Supply. When I connect both of the 6 pin PCI-E connectors from the psu to the gpu and try to run the computer, it starts for a second and shuts down. I did the paper clip test and the psu was working fine. I used a wattage calculator online and it seemed that I only needed roughly 500W to run the whole rig and was under the impression that 550W PSU would be ok... should I get a higher wattage psu? I searched the forums and people were suggesting psu from 550W to 850W for the gpu so I am not sure if I am not connecting everything correctly or if I need to buy another psu.
OP here. If my power supply is enough to power this then I am not sure what is wrong.
Another thing is my mother board will not post (no beep) even with integrated graphics card. So my mobo might be bad as well.
I tried to connect the gpu into another computer that works with a 500W psu and the same thing happened: all the fans spin for a second, the system comes on for a second and then shuts down.
Another thing that was weird was the when I connected one 6 pin from PSU to GPU, and another one from GPU to a 120mm fan that is not connected to anything, the system runs but still doesn't display anything on the monitor (and still no beep from mobo).
I am supposed to connect both the 6 pin connector directly in the PSU, correct?
From this, I am thinking maybe my mobo is bad AND my gpu is bad. (or maybe I need a more powerful PSU?) Any suggestions?